Luca Silvestrini Page 1IFAE, 21/4/2006
Flavour Physics Stefano Giagu & Luca Silvestrini
Introduction Recent experimental & theoretical developments:
Kaon physics (M. Dreucci, P. Massarotti)B physics (P. Gambino, T. Cartaro, N. Neri, E. Baracchini, M. Morello)BS,C physics (P. Santorelli, R. Ferrandes, G. Salamanna, G. Passaleva)
Impact on the SM and beyond: Unitarity triangle analysis in the SM and beyond (V. Vagnoni) Constraints on SUSY parameters (V. Porretti, P. Paradisi)ConclusionsOutlook: the role of flavour physics in the era of LHC
Luca Silvestrini Page 2IFAE, 21/4/2006
INTRODUCTION The Standard Model works beautifully up to a few hundred GeV's, but it must be an effective theory valid up to a scale Λ Mplanck:
EW scale
Has accidental symmetries
Violates accidental symmetries
Luca Silvestrini Page 3IFAE, 21/4/2006
How can we explore NP with processes involving only SM particles?
I. Electroweak gauge symmetry spontaneously broken tree-level relations between EW observables (masses, couplings, ...)
quantum corrections computable and sensitive to higher-dim operators
The LEP glorious legacy of precision EW fits: Λ > 2-10 TeV!!
HOW TO PROBE NEW PHYSICS:I. ELECTROWEAK SYMMETRY BREAKING
Luca Silvestrini Page 4IFAE, 21/4/2006
Three flavours of fermions with same gauge quantum numbers but different mass.
Flavour eigenstates are not weak interaction eigenstates weak interactions change flavour
Accidental symmetry of the SM: Neutral current weak interactions conserve flavour at the tree level, GIM suppression of loop contributions
quantum corrections computable and sensitive to higher-dim operators
FLAVOUR & CP VIOLATION IN THE SMHOW TO PROBE NEW PHYSICS:
II. FLAVOUR PHYSICS
Luca Silvestrini Page 5IFAE, 21/4/2006
• All flavour violation from charged current coupling: CKM matrix V
• and A from CC decays – tree-level, SM• Top quark exchange dominates FCNC loops:
third row (Vtq) determines FCNC's sensitive to new physics
V CKM= 1−2
2 A3−i
− 1−2
2A2
A31−−i −A2 1O 4
_ _
Luca Silvestrini Page 6IFAE, 21/4/2006
Luca Silvestrini Page 7IFAE, 21/4/2006
Luca Silvestrini Page 8IFAE, 21/4/2006
Luca Silvestrini Page 9IFAE, 21/4/2006
Luca Silvestrini Page 10IFAE, 21/4/2006
Error anatomy of BRγ
Total error 8% dominated by charm mass Can be partially resolved by NNLO
Misiak, PG 2001
mc enters the phase factordue to normalization
= 0.581±0.017
and the NLO matrix elements
Misiak & PG
Talk by P. Gambino
Luca Silvestrini Page 11IFAE, 21/4/2006
NNLO status report
Misiak, Moriond 2006
Luca Silvestrini Page 12IFAE, 21/4/2006
Forward-Backward asymmetry in B K* l+ l-
Luca Silvestrini Page 13IFAE, 21/4/2006
Babar:
Belle:
Luca Silvestrini Page 14IFAE, 21/4/2006
Talk by M. Morello
Luca Silvestrini Page 15IFAE, 21/4/2006
Talk by N. Neri
Luca Silvestrini Page 16IFAE, 21/4/2006
Talk by M. Morello
Luca Silvestrini Page 17IFAE, 21/4/2006
Luca Silvestrini Page 18IFAE, 21/4/2006
Luca Silvestrini Page 19IFAE, 21/4/2006
Luca Silvestrini Page 20IFAE, 21/4/2006
A handle on non-factorizing BS decays using SU(3)
Talk by R. Ferrandes
Luca Silvestrini Page 21IFAE, 21/4/2006
R. Ferrandes
Luca Silvestrini Page 22IFAE, 21/4/2006
Bc decays in a quark model
P. Santorelli
Luca Silvestrini Page 23IFAE, 21/4/2006 P. Santorelli
Luca Silvestrini Page 24IFAE, 21/4/2006Talk by G. Salamanna
Luca Silvestrini Page 25IFAE, 21/4/2006 G. Salamanna
Luca Silvestrini Page 26IFAE, 21/4/2006 G. Salamanna
Luca Silvestrini Page 27IFAE, 21/4/2006
Luca Silvestrini Page 28IFAE, 21/4/2006 G. Salamanna
Luca Silvestrini Page 29IFAE, 21/4/2006
Luca Silvestrini Page 30IFAE, 21/4/2006 G. Salamanna
Luca Silvestrini Page 31IFAE, 21/4/2006
Luca Silvestrini Page 32IFAE, 21/4/2006 G. Salamanna
Luca Silvestrini Page 33IFAE, 21/4/2006
Luca Silvestrini Page 34IFAE, 21/4/2006 G. Salamanna
Luca Silvestrini Page 35IFAE, 21/4/2006
From UTfit:
Luca Silvestrini Page 36IFAE, 21/4/2006
BR(bcl), BR(BD(*)l)
BR(bul), BR(Bl)
md, md/ms
ACP(bccs) (J/ K, ...)
ACP(bddd, uud) (, )
BR(bcud, cus) (DK, ...)
BR(B)
BR(B)/BR(B)
K (CP violation in K mixing)
Flavour summarized on the plane
_
_
_ _
CC
CC
NC
CC
CC/NC
CC
CC
NC
NC
_
Luca Silvestrini Page 37IFAE, 21/4/2006
Luca Silvestrini Page 38IFAE, 21/4/2006
Luca Silvestrini Page 39IFAE, 21/4/2006
Luca Silvestrini Page 40IFAE, 21/4/2006
Luca Silvestrini Page 41IFAE, 21/4/2006
Using:md, ms, |Vub/Vcb|, sin 2CP violation in B mixing (new from BaBar):
PRELIMINARYAccuracy comparableto the SM fit!
Luca Silvestrini Page 42IFAE, 21/4/2006
C=1.15±0.13[0.97,1.55]SM: C=1
CBd=1.38±0.45[0.69,2.54]
d [°]=-4.0±2.2[-8.2,0.8]
Get a nonvanishing Bd because of SMfit discrepancyCBs now constrained by msBs still unconstrained
PRELIMINARY
Luca Silvestrini Page 43IFAE, 21/4/2006
Luca Silvestrini Page 44IFAE, 21/4/2006
N. Neri
Luca Silvestrini Page 45IFAE, 21/4/2006
THE MSSM
• In the MSSM, two classes of contributions to FCNC's:● Supersymmetrization of SM contributions (W w, t t) + H
● pure SUSY contributions: g – q • second class requires new sources of flavour
violation in squark mass matrices
~ ~
~ ~
Hall, Kostelecky & Raby; Gabbiani et al.
Luca Silvestrini Page 46IFAE, 21/4/2006
A Model-Independent Analysis
• We consider a MSSM with generic soft SUSY-breaking terms, but– dominant gluino contributions only– mass insertion approximation
four insertions AB=LL, LR, RL, RRNow full NLO available!
d Ai d B
jδd ij AB
Talk by V. Porretti
Think of 's as SUSYequivalent of CKM mixing
Luca Silvestrini Page 47IFAE, 21/4/2006
CONSTRAINTS ON 's• contribute to Kaon mixing:
constraints from ΔmK & εK• contribute to B mixing:
constraints from ΔmB & sin2β
• contribute to Bs mixing and b s decays: constraints from ΔmBs, b s, b sl+l-
• for reference, choose mgl=msq=350 GeV
δd 12 ABδd 13AB
δd 23 AB
Luca Silvestrini Page 48IFAE, 21/4/2006
Luca Silvestrini Page 49IFAE, 21/4/2006
THE SUSY FLAVOUR PROBLEM
• Strong constraints on SUSY breaking mechanism:–Flavour-universal breaking?–Flavour symmetry?
Luca Silvestrini Page 50IFAE, 21/4/2006
Luca Silvestrini Page 51IFAE, 21/4/2006
Talk by F. Mescia
Luca Silvestrini Page 52IFAE, 21/4/2006
LHCb performance with 2fb-1 (1 year)
C7eff/C9eff with 13% errorNP search
σ(ACPdir) ≈ 0.01
σ(sin2β) ≈ 0.022
0.01 ps-1
σ(φs) ≈ 2°
σ(α) ≈ 10°
σ(γ) ≈ 14°
σ(γ) ≈ 6°
σ(γ) ≈ 8°
σ(γ) ≈ 5°
Precision
σ(sin2β) ≈ 0.018
CDF17.33±0.35 ps-1
σ(α) ≈ 7-15°
σ(γ) ≈ 6.5°
B-factories 2ab-1
0.8216kBd → J/ΨKSβ
Luca Silvestrini Page 53IFAE, 21/4/2006
LHC performance after 5 years
After 5 years: σ SM expectation
φs(Bs→ ccss) ~0.013 ∼0.035
Br(Bs→ µ+µ−) ~0.7×10−9 ~3.5×10−9
γ (DsK, DK) ~1° ~60° (tree only) γ (ΚΚ+ππ) ~2° ~60° (tree + penguin)
Talk by G. Passaleva
Luca Silvestrini Page 54IFAE, 21/4/2006
CONCLUSIONS• Recent data from B-factories and the Tevatron
close the possibility of order-of-magnitude NP effects.
• New sources of CPV can still be present in b->s transitions: need LHCb + superB.
• In a few years, will constrain NP at the 10% level in all sectors. Theoretical accuracy approaching the SM one.
• Flavour problem open: still miss explanation of flavour structure (and of apparent MFV)
Luca Silvestrini Page 55IFAE, 21/4/2006
THE ROLE OF FLAVOUR PHYSICS IN THE LHC ERA
• Most probably see some NP at LHC, but not the full spectrum of NP particles;
• Even if full spectrum seen, still many parameters to be determined;–Need flavour physics as much as LC
• Flavour remains the most powerful probe of scales higher than the reach of LHC
Luca Silvestrini Page 56IFAE, 21/4/2006
EXAMPLE I: LFV @ LARGE tan
Luca Silvestrini Page 57IFAE, 21/4/2006
Luca Silvestrini Page 58IFAE, 21/4/2006
EXAMPLE II: SUSY-GUTs
• In an SU(5)-like GUT, quark and leptons are unified, so also squark and sleptons.
• After running down to weak scale, one has:
• Correlations between quark & lepton FCNC!
Luca Silvestrini Page 59IFAE, 21/4/2006
Im (d23)RR vs. Re (d23)RR
any BR τ μγ
m q=m g350 GeV
BR τ μγ 6⋅10−7
BR τ μγ 1⋅10−7 BR τ μγ 1⋅10−8
Ciuchini et al, PRL
Luca Silvestrini Page 60IFAE, 21/4/2006
Flavour physics in the LHC era will play a leading role in determining the relevant NP
model parameters, in exploring higher energies and in providing us with clues on the
physics at MGUT.
Top Related